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(No Model.) V. M. RISGH. I WREST PLANK FOR PIANOS.

No. 439,688; Patented Nov. 4f

UNITED STATES PATENT OFFICE.

VINCENT M. RISOH, OF TORONTO, CANADA, ASSIGNOR OF ONE-HALF TO THOMAS GABRIEL MASON, OF SAME PLACE.

WREST-PLANK FOR PIANOS.

SPECIFICATION forming part of Letters Patent No. 439,688, dated November 4, 1890.

Application filed June 12, 1890. Serial No. 355,142. (No model.)

To all whom it may concern:

Be it known that I, VINCENT MICHAEL RISCH, a citizen of the Dominion of Canada, residing at the city of Toronto, in the county of York and Province of Ontario, Canada, have invented certain new and useful Improvements in the Vrest-Plank or Pin-Block in Piano-Fortes; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the manufacture of the wrest-plank or pin-block in piano-fortes, its object being to do away with the bolts, screws, and other like devices which have hitherto been used for binding together the piano-frame and the several parts of the wrestplank or pin-block, and thereby make it absolutely firm and unyielding. l

The construction and mode of operation of my said invention appears more fully by reference to the accompanying drawings, in which like letters referto like parts throughout, and in which- Figure l is aview of the old style, and Fig. 2 is a view showing my improvements.

The wrest-plank is that part of the pianoforte in which the tuning-pins are driven and fastened, and is glued to the frame or back of the piano. It consists of two parts. The first part is a plank (marked A in the accompanying drawings) running the full length of the back, made of maple or other suitable hard wood, and glued to the frame or back of the piano-forte. On this a veneer of maple or other suitable wood (marked B in the accompanying drawings) is glued. The second part consists of three or more layers of veneer, (marked O C O,) made of maple or other suitable wood, glued together usually with the grain of each running at right angles or diagonally to the next one.

D is a portion of the upright frame of the piano, made of pine or other softwood. EE

are heavy planks, usually made of hard wood, running the whole length of the frame and forming part thereof.

They are glued to D for the purpose of strengthening the back and top of the frame.

F F are dovetailed keys, made of hard wood, having one end embedded in and passing through both parts of the wrest-plauk A B vO O and the other end embedded in the pianoframe E. These keys are usually let into the wrest-plank and into the piano-frame to a depth of three-fourths of an inch or more. The keys are placed throughout the whole length of the wrest-plank at suitable distances, (usually about fourteen inches apart,) and they serve to bind together the several parts of the wrest-plank and the whole to the piano-trame. Hitherto the piano-frame and the several parts of the wrest-plank or pinblock have been bound together by bolts, screws, and other like devices. The defect in this mode of construction is that, however well the wood of which the frame and wrestplank is composed may have been seasoned, it will in time shrink to a certain extent, whereupon the bolt or screw becomes somewhat loosened and the wrest-plank fails to retain that absolute firmness which is essential to its usefulness. By my invention these defects are obviated, and the several parts are so bound together as to be absolutely unyielding to the strain of the strings, even though the wrest-plank should shrink or the glue joints become affected by dampness or other causes.

I claim nothing in respect to the general mode of construction either of the wrest-plank or of the piano-frame. These may be made as indicated in the drawings, or in any other suitable manner.

Vhat I claim, and desire to secure by Letters Patent, is-

In a piano-forte, the combination, with the Wrest-plank A B C O and the several parts of the frame D E E, of the dovetails and dowels of wood E F', in the manner and for the purpose aforesaid.

V. H. RISOH.

Witnesses:

H. GAEDHoUsE, E. A. PRINGLE. 

